A powerful storm pounded California with rain and snow Tuesday, leaving one person dead and two others missing after they were swept away by floodwaters in a canal, while a tornado touched down in Sacramento County.

The National Weather Service said the tornado touched down at 1:40 p.m. a few miles outside the town of Galt. NBC affiliate KCRA in Sacramento reported that a tin roof on a barn was blown off and took down utility lines. No other damage was reported.

The stormy weather raised concerns it could keep people from voting on Election Day with flash flood warnings in effect in some areas.

In Southern California a current in a canal in Ontario swept six people away, killing one, the Ontario Fire Department said. Three others were rescued by firefighters and were being treated at a nearby hospital. Crews continued searching for two others amid the downpour.

Heavy rain drenched Orange County, where several very close U.S. House races could determine which party controls Congress. The Republican Party of Orange County urged members to vote early and avoid getting stuck in the rain on Election Day.

“Election day lines are long and typically one to two hours long. Don’t risk getting caught waiting in the rain to cast your ballot,” an email sent by the party Monday said.

As of 6 p.m. Tuesday, Long Beach had received .85 inches of rain, with no immediate reports of any damage or flooding.

The storm, which arrived Monday and was forecast to continue through Wednesday, prompted evacuation orders in parts of Southern California, including in the Santa Ana Mountains’ Bond Fire burn scar area.In Northern California, meterologists warned the heavy rainfall could lead to debris flows and flash flooding in the burn scars of the Colorado and River wildfires.Between 1 and 3 inches of rainfall are expected through Wednesday in the Los Angeles area’s coast and valleys.

The foothills and mountains could see up to 5 inches.

Meanwhile, in the mountains, peaks above 6,000 feet elevation could get 6 to 12 inches of snowfall, with 20 inches possible locally.

The National Weather Service issued a winter storm warning for the greater Lake Tahoe area on Tuesday as heavy snow fell in the region, causing backups in major highways in the area. The agency warned driving in the region would be extremely difficult, if not impossible.

“Be prepared for whiteout conditions and sub-zero wind chills along ridgelines and near the mountain passes,” the agency said in its alert, adding that the hazardous conditions will affect motorists during peak commute times.